Important, high-quality sites receive a higher PageRank, which Google remembers
each time it conducts a search. Of course, important pages mean nothing to you
if they don't match your query. So, Google combines PageRank with sophisticated
text-matching techniques to find pages that are both important and relevant to
your search. Google goes far beyond the number of times a term appears on a page
and examines all aspects of the page's content (and the content of the pages
linking to it) to determine if it's a good match for your query.